What is the mass of 0.23 moles of CF4? *

Apiece of metal with a length of 1.42 cm was measured using four different instruments. which of the following measurements is the most accurate?

The bond energy for the van der waals bond between two helium atoms is 7.9×10−4ev. assuming that the average kinetic energy of a helium atom is (3/2)kbt, at what temperature is the average kinetic energy equal to the bond energy between two helium atoms

As changes in energy levels of electrons increase, the frequencies of atomic line spectra they emit